The present invention relates to a process for producing a flaked cellulose-based thermal- and/or acoustic-insulating material.
The majority of the known processes for producing insulating flakes of the type in question envisage the use, as starting material, of waste paper or cardboard, and usually envisage a series of steps in which said material is first treated mechanically for shredding it and reducing it into flakes, and is then treated via a series of additives for sanitization of the material, for example bioinhibitors (boric acid, borax, etc.).
The insulating materials obtained from the above processes present the drawback of containing various undesirable substances, deriving from the original material (for example, magazines, newspapers, etc.), such as calcium carbonate, inks, glazings, etc., which involve problems both in relation to conservation of the material and in relation to its insulating performance.
Likewise known in the art is a type of process for producing cellulose-based flaked insulating material, which envisages the use of paper-mill sludge as starting material. This process is, for example, described in the document No. WO2010/067338. The industrial process described in the above document envisages, in its essential steps, mixing of paper-mill sludge with waste paper and possibly with first-extraction cellulose obtained directly from wood, milling of the material thus mixed until the desired size is obtained, treatment of the material in a pulper for separating and isolating the individual cellulose fibres, a further mechanical treatment in a mill, and finally a step of drying of the material. This process envisages introduction of a series of additives into the pulper, for example fungicides, flame-retardants, colouring agents, etc.